http://www.instructables.com/id/DIY-Flexible-Printed-Circuits/

Get some thin sheets of polyimide which have copper on one or both sides. Polyimide is a yellow polymer with a high melting temperature and is sometimes called Kapton. A common type of copper-coated polyimide is DuPont "Pyralux" material.

Pyralux sheets come in many different varieties of polyimide thickness, copper thickness and adhesive thickness (the "adhesive" is between the copper and polyimide holding everything together.) Copper thickness is given in oz per square foot, while adhesive and Kapton thickness is given in mil (1 mil =0.001 inch).

Pyralux LF7062 (pictured) has 1/2 oz Cu, 1/2 mil adhesive and 1 mil Kapton. This works OK but is a bit thin and crinkly for the printer to handle.
LF9120 has 1 oz Cu, 1 mil adhesive and 2 mil Kapton - seems to work best in the printer
LF9210 has 2 oz Cu, 1 mil adhesive and 1 mil Kapton - stiffer, but works OK

Other options are double sided copper ( a sandwich of Cu/Kapton/Cu held together with adhesive) and a roughened surface, denoted by R at the end of the part number.

The roughened sheets and double sided sheet work OK. However, Pyralux with 2 oz or thicker copper can be difficult to feed to the printer, especially if there is copper on both sides.

See if you can get a free sample from DuPont. Occasionally, Pyralux sheets turn up on eBay.

Cut the Pyralux sheets to 8.5x11 or 8.5x14 inches with scissors or a knife. Avoid smudging the copper with fingerprints or oil, which can block the etch solution later. To protect the printer, try to keep the edges relatively flat and free of burrs.

For direct printing on the copper film, locate a solid-ink printer. These are commonly confused with laser printers, but instead print melted wax. Unlike most inkjets, the wax makes a good protective layer for copper etching, and unlike laser printers, solid ink printers don't rely on locally charging the paper surface, which could be troublesome when the paper is replaced by a copper sheet.

Some models are Tektronix Phaser 840, 850, 860, and Xerox Phaser 8200, 8400, 8500, 8560, and 8860. You might find one in an office. Most Phaser models are regular laser printers, so check under the hood for the solid ink blocks (pictured) if you're not sure.

If you don't have access to a solid ink printer, the "toner transfer" iron on method, using a laser-printed design, could replace this step.
_______________________________________________
sudo-discuss mailing list
sudo-discuss@lists.sudoroom.org
http://lists.sudoroom.org/listinfo/sudo-discuss